In general, cancer patients are treated by injection of special antibiotics, and patients who need pain management are treated by injection of anodynes for reducing pain. When medicinal fluids such as special antibiotics or anodynes are excessively provided, unlike other general medicinal fluids, they may cause patients to lapse into a comatose state or suffer death from shock. However, when such fluids are not sufficiently provided, the purposes of the medicinal fluids cannot be obtained. Accordingly, it is very important to inject an accurate amount within an allowable range.
Syringes have been used to inject medicinal fluids in most cases of the related art. However, when syringes were used, the dosage of medicinal fluids depended on the skill level of people who handle the syringes, etc. and they were necessarily involved every time the patient required an injection of medicinal fluids, so it was very difficult to maintain dosage per hour at an appropriate level. That is, it is difficult to manage and maintain the dosage of medicinal fluids.
Further, dosage adjusters that are installed on hoses for injecting medicinal fluid have been used to adjust the dosage of the medicinal fluids. However, the dosage was adjusted by the degree of pressing the hoses by the dosage adjusters, so it was difficult to accurately inject a desired amount of medicinal fluids in accordance with the momentarily changing states of patients.